Method of cracxing petroleum vapors



May 2, 1933. c. w. ANDREWS ET AL METHOD OF CRACKING PETROLEUM VAPORS J w wa ma m Patented May 2, 1933 UNITED STATES PATENT critical CHARLES W. ANDREWS, OF GHICAGO, .5[LLINOIS, AND REGINALD D. ROGERS, OF

BAYONNE, NEW JERSEY, ASSIGNORSTO C. 1?. '1. DEVELOPMENT GOMPANY, O'F CHICAGO, ILLINOIS, A CORPORATION OF. DELAWARE METHOD OF (CRACKING- IEET'ROLEUM VAfiORS Application filed March a, 1930. Serial no. 432,655.

This invention relates to a new and improved method of cracking petroleum vapors, and while particularly adapted for use in connection with the vapors given 02 while cok- 3 ing heavy petroleum residues, or the like, it is also adapted for use in connection with vaporization by other methods.

In our prior application Serial No. 368,997, filed June 6, 1929, We have shown a form 110 of oven heated from below by flues under the sole of the oven, which oven is adapted for the coking of heavy residues, sa id coking being materially speeded up by heating the incoming heavy residues or oils to a high 35 temperature.

In our prior application Serial No. 413,207, filed December v11, 1929, we have carried this operation further by adding another step, namely, the injection of hot gas into the oven itself in order to speed up the operation.

It is an object of this present invention to provide a new and improved method whereby the vapors released may be further heated to a temperature around 1000 to 1200 F. and

then quickly cooled to the temperature at which the reactions are arrested. It is also an object of this invention to provide a means for quickly cooling such vapors.

Another object of the invention is to carry on such heating by the injection of non-oxidizing gases, preferably flue gases, into the arising gaseous current in order to heat quickly the outgoing vapors to the temperatures desired. 7

A further object of the invention is to control the temperature and quality of such heating gases by adding thereto combustible gases. I

It is an additional object to heat the ascending vapors by any suitable means such as a tubular heater so arranged that the tubes can be readily cleaned.

It is also an object to provide a method 45 of this character for the treatment of high boiling point hydrocarbons having substantial percentages of cokable carbon.

Other and further objects will appear as the description proceeds.

live have shown somewhat diagrammatically in the accompanying drawing, certain preferred embodiments of an apparatus adapted to carrying out our improved method.

Figure 1 is a transverse section through one form of apparatus; and 5 Figure 2 is a similar view of a modified form of apparatus.

In the drawing, a coking chamber 11 is shown as having a floor 12, preferably formed of refractory material and heated from be- @0 low through flues 13. Recuperator fiues 1 1 are shown located below the combustion fiues 13 and these flues communicate through passages 15 with the ofi'take header 16. This header 16 leads to passage 17 which communie5 cates with the stack 18. The passage 17 is controlled by a valve 19. A by-pass passage 20 leads from the passage 17 at a point between the -valve 19 and the oven, and this passage 20 extends to a junction with the ofi'take passage 21 leading from the coking chamber 11. The passage 20 terminates in a downwardly extended discharge end 22 which is partly closed by a deflecting plate 23. The passage 20 is shown as covered with a heat insulating layer 2 1. The passage 20 is controlled by valve 25.

A nozzle 26 connected to a pipe 27 con trolled by valve 28, is shown extending into the passage 20 for the purpose of introducing steam or other fluid under pressure to control flow through the passage. The nozzle 29 also extends into the passage 20, this nozzle being connected to pipe 30 controlled by valve 31, and pipe 32 controlled by valve 33.

The coking chamber 11 is shown as provided with lateral Walls 34 which may be formed of refractory material and with a metal roof 35 having a heat insulating covering 36. Nozzles 37 controlled by valves 38 are shown introduced through the roof 35 for the purpose of introducing the petroleum or other heavy hydrocarbon material in liquid form into the coking chamber for treatment.

The ofltake passage 21 is shown as extending horizontally at 39 into communication with the cooling chamber 40. This chamber 40 contains a rotary member 41 rotated by a motor or other source of power 42. The member 41 has a cylindrical portion 43 carrying a plurality of radially extending tubes 44 open at both ends. The spray nozzle 45 discharges into the open side of the member 41 and is fed through pipe 46, controlled by valve 47. The lower portion of the chamber 40 is provided with a collecting sump 48, with an ofltake pipe 49 controlled by valve 50. The passage 51 leads from the chamber 40 to carry off uncondensed vapors or gases.

The form of construction shown in Figure 2 is similar in many respects to that described above. The by-pass passage 52 leading from the ofl'take flue 17 communicates with the interior of a recuperator 53 provided with a plurality of bafiles 54. The gaseous products of combustion are then carried ofi through the secondary ofltake flue 55 to the stack 56. The

recuperator 53 is provided with the flues 57 which lead from the coking chamber 11 to the collecting chamber 58 from which they pass through passage 59 to the cooling chamber 40.

A pipe 60 controlled by valve 61 leads to a spray nozzle 62 adapted to spray into the rotating member 41. The by-pass passage 52 is provided with a nozzle 29 and pipes 30 and 32, controlled by valves 31 and 33 respectively, in the same manner as the construction of Figure 1. The passage 52 is also controlled by the valve 25, and is covered by insulating covering 63.

In the operation of the apparatus shown in Figure 1, the floor 12 of the oven is brought to a coking and cracking temperature by combustion in the fiues 13, the products of combustion being led off through passage 17 to the stack 18. When the floor has been brought approximately to this temperature, heavy hydrocarbons in liquid form, such as petroleum residue, are introduced into the nozzle 37 into the chamber and deposited continuously on the floor. The volatile constituents of the hydrocarbon are driven off by the heat, and the non-volatile residue is coked. The rate of feed and the rate of heat input to the floor are preferably so co-ordinated that only a comparatively small quantity of liquid is maintained in a layer on the floor and on the gradually thickening layer of coke formed on the floor. At intervals the process is stoppedand coke removed from the cor.

The volatile products of the process, which will contain all of the various volatile congases going through passage 17 will normally be at temperatures from 1200 to 1500 F.

By a suitable manipulation of the valves 19 and 25, any desired proportion of these flue gases may be carried through by-pass passage 20 to the downturned end 22 and deflected by the plate 23 to mingle with the vapors of the coking process.

A steam or gas injector 26 may be used to control the velocity and amount of these gases. The nozzle 29 may be used for the introduction of air to complete the combustion of any uncombined oxygen in the products of combustion and to render these products non-oxidizing. This secondary combustion will also serve to control the temperature of the gases.

If necessary, or desirable, to cause additional combustion to raise the temperature, gaseous or liquid fuel may be introduced to nozzle 29 through pipe 32 controlled by valve 33. Such fuel may be introduced alone if there is uncombined oxygen in the flue gases, or air may be introduced with the fuel through the nozzle 29, the air being admitted through pipe 30 controlled by valves 31. By various modifications of the use of this nozzle and pipes, the temperature of the gases may be controlled and also they may be rendered non-oxidizing in character.

The admixture of the flue gases with the vapors from the coking and cracking process will raise the temperature of the gases to a cracking temperature of from 1000 to 1200 F. The gases are then cooled by the spray of oil from nozzle 45, this spray being further admixed with the gases by the spraying action of the rotating member 41 and the tubes 44. The cooling oil will collect in the sump 43 together with any of the vapors which may be condensed out by the action of the cooling oil. The control of the temperature of the cooling oil will put a low boiling limit on the oil passed over.

The uncondensed vapors are carried off through pipe 51 from which they may be carried to any desired condensing, fractionating or washing apparatus. The velocity of passage of the gases through the ofltake passage 21 from the coking chamber 11 may be controlled by the pressures and suctions in the system and the rotating member 41 may be designed to act as a suction fan.

The effective passage area of the passage 21- and its length may be so designed in relation to the volume of gases and their velocity in any installation, that the period during which the vapors are maintained at the high cracking temperature may be within the desired limits.

The form of construction shown in Figure 2 operates in a similar manner. The difference here is that the products of combustion are not mixed with the vapors from the coking chamber, but serve to heat these vapors by conduction through the walls of the tubes 57 The temperature of the products of combustion may be controlled by secondary or additional combustion from the nozzle 29, as in the previous form of apparatus. In this form of apparatus, however, the question as to whether the gases are oxidizing or neutral will be of no importance since they do not contact with the petroleum vapors.

The length and size of the tubes 57 and the velocity of the vapors through them may be so controlled as to keep the vapors at the desired cracking temperature for the desired period of time. It will be understood that such desired period of time in carrying out the method with both forms of apparatus may be in the nature of fractions of a sec- 0nd, and the sizes of the parts and velocities of the vapors may be controlled with the degree of accuracy necessary for such periods of time.

While we have shown certain preferred embodiments of apparatus adapted for carrying out our invention, it will be obvious that it may be carried out in other forms of apparatus and in other ways, and we contemplate such changes and modifications as come within the spirit and scope of the appended claims.

We claim:

1. The method of convertin and cracking high boiling point hydrocaions and concurrently coking part of the high boiling point hydrocarbons which comprises feeding them, into a chamber, heating them in said chamber to a cracking and coking temperature by externally heating the chamber, maintaining the chamber under approximately atmospheric pressure, and further cracking the vapors from the cracking operation in the chamber by mixing with them highly heated gases, qulckly cooling the vapors to a temperature at which the reactions are arrested, and recovering the condensible lighter compounds and recovering from the chamber coke suitable for metallurgical purposes.

2. The method of converting and cracking high boiling point hydrocarbons containing in excess of 5% coke forming carbon and concurrently coking part of the high boiling point hydrocarbons which comprises feeding them into a chamber, heatin them in said chamber to a cracking and co ing temperature by externally heating the chamber, maintaining the chamber under approxi- CHARLES W. ANDREWS. REGINALD D. ROGERS. 

